The US Justice Department and the Federal Trade Commission (FTC) are looking
at Apple's new subscription terms for selling content via its iPhone and
iPad devices.

According to the Wall Street Journal, the inquiry is at a "preliminary" stage and may not develop into a formal investigation or result in any actions taken.

The anti-trust regulators are looking into whether Apple is breaking the law by insisting publishers use its subscription system to collect payments from iPhone and iPad users.

Some app makers are unhappy with Apple's plans to take a 30pc cut on all revenue from online subscriptions.

Apple is also prohibiting publishers from offering links within their applications to websites where consumers could purchase their products or from offering a better deal anywhere outside of its App Store.

The European Commission said it was "monitoring market developments carefully" on Apple's subscription service but an official investigation appears unlikely as commissioners believe rivalry in the field is increasing.